'\"macro stdmacro
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.TH PMDATRACE 1 "PCP" "Performance Co-Pilot"
.SH NAME
\f3pmdatrace\f1 \- application-level transaction performance metrics domain agent
.SH SYNOPSIS
\f3$PCP_PMDAS_DIR/trace/pmdatrace\f1
[\f3\-d\f1 \f2domain\f1]
[\f3\-l\f1 \f2logfile\f1]
[\f3\-A\f1 \f2access\f1]
[\f3\-I\f1 \f2port\f1]
[\f3\-M\f1 \f2username\f1]
[\f3\-N\f1 \f2buckets\f1]
[\f3\-T\f1 \f2period\f1]
[\f3\-U\f1 \f2units\f1]
.SH DESCRIPTION
.B pmdatrace
is a Performance Metrics Domain Agent (PMDA) which exports transaction
performance metrics from application processes which use the
.I pcp_trace
library described in
.BR pmdatrace (3).
.PP
A brief description of the
.B pmdatrace
command line options follows:
.TP 5
.B \-d
It is absolutely crucial that the performance metrics
.I domain
number specified here is unique and consistent.
That is,
.I domain
should be different for every PMDA on the one host, and the same
.I domain
number should be used for the same PMDA on all hosts.
.TP 5
.B \-l
Location of the log file.  By default, a log file named
.I trace.log
is written in the current directory of
.BR pmcd (1)
when
.B pmdatrace
is started, i.e.
.BR $PCP_LOG_DIR/pmcd .
If the log file cannot
be created or is not writable, output is written to the standard error instead.
.TP 5
.B \-A
Host-based access control for
.BR pmdatrace .
.I access
must be either an allow or deny specification, using either
allow:hostspec:maxconns or disallow:hostspec, where `allow' and `disallow' are
keywords, `hostspec' is a host specification conforming to the format used by
both
.BR pmcd (1)
and
.BR pmlogger (1),
and `maxconns' is the maximum number of connections allowed from a given
`hostspec'.
Using a maximum connections of zero specifies an unlimited number of
connections for the accompanying `hostspec'.
.TP 5
.B \-I
Communicate with
.I pcp_trace
clients via the given Internet
.IR port .
This can alternatively be specified by setting
.B $PCP_TRACE_PORT
in the environment to some valid port number (use of the
.B \-I
option overrides this).
The default port number is 4323.
.TP 5
.B \-T
\f2period\f1 defines the aggregation period used to compute the recent
averages and extrema.
Specified as a time interval using the syntax described in
.BR PCPIntro (1)
for the common
.B \-t
PCP argument, e.g. \c
.B "30 seconds"
or
.BR "1 min" .
The default is 60 seconds.
.TP 5
.B \-M
User account under which to run the agent.
The default is the unprivileged "pcp" account in current versions of PCP,
but in older versions the superuser account ("root") was used by default.
.TP 5
.B \-N
Internally, the aggregation \f2period\f1 is divided into \f2bucket\f1
divisions, and the rolling average is recomputed every
\f2period\f1/\f2bucket\f1 seconds.
For example, the defaults correspond to \-T 60 and \-N 12, which means
the average is recomputed every five seconds for a period covering the
prior 60 seconds.
.TP 5
.B \-U
This option allows the dimension and scale associated with the observation
value metric to be configured.
\f2units\f1 is a comma-separated string of six integer values, which are the
space dimension, time dimension, count dimension, space scale, time scale, and
count scale, respectively.
The default dimension and scale is ``none'', which is equivalent to
presenting ``0,0,0,0,0,0'' as the argument to \-U.
The units associated with a metric are most easily viewed using the \-d
(metric description) option to
.BR pminfo (1).
The Install script described below steps through this option quite explicitly,
so it is recommended that the Install script be used for building up the
\f2units\f1 specification.
.PP
Essentially, the exported metrics provide statistics on the time for
completion of each transaction, and an average count of transactions completed
and watch points passed over a given time \f2period\f1.
.SH INSTALLATION
In order for a host to export the names, help text and values for the Trace
performance metrics, do the following as root:
.PP
.ft CW
.nf
.in +0.5i
# cd $PCP_PMDAS_DIR/trace
# ./Install
.in
.fi
.ft 1
.PP
If you want to undo the installation, do the following as root:
.PP
.ft CW
.nf
.in +0.5i
# cd $PCP_PMDAS_DIR/trace
# ./Remove
.in
.fi
.ft 1
.PP
.B pmdatrace
is launched by
.BR pmcd (1)
and should never be executed directly.
The Install and Remove scripts notify
.BR pmcd (1)
when the agent is installed or removed.
.SH FILES
.PD 0
.TP 10
.B $PCP_PMCDCONF_PATH
command line options used to launch
.B pmdatrace
.TP 10
.B $PCP_PMDAS_DIR/trace/help
default help text file for the trace metrics
.TP 10
.B $PCP_DEMOS_DIR/trace/*
example programs which use the
.I pcp_trace
library
.TP 10
.B $PCP_PMDAS_DIR/trace/Install
installation script for the
.B pmdatrace
agent
.TP 10
.B $PCP_PMDAS_DIR/trace/Remove
undo installation script for
.B pmdatrace
.TP 10
.B $PCP_LOG_DIR/pmcd/trace.log
default log file for error messages and other information from
.B pmdatrace
.PD
.SH "PCP ENVIRONMENT"
Environment variables with the prefix
.B PCP_
are used to parameterize the file and directory names
used by PCP.
On each installation, the file
.B /etc/pcp.conf
contains the local values for these variables.
The
.B $PCP_CONF
variable may be used to specify an alternative
configuration file,
as described in
.BR pcp.conf (5).
.SH SEE ALSO
.BR PCPIntro (1),
.BR pmcd (1),
.BR pmtrace (1),
.BR PMAPI (3)
and
.BR pmdatrace (3).
